Across the country, 190 municipalities either tax plastic grocery bags or have banned them altogether.

In California, Los Angeles County banned them beginning January 1st of this year, and the California state legislature is currently entertaining a bill that would ban them statewide. In most places, paper bags can be purchased at the checkout in case one has forgotten to bring their own bag.

The justification for the bans have been the negative economic and environmental effects of plastic bags. In other words, forcing people to bring their own bags saves money for municipalities and helps save the planet.

Ban supporters tend to be passionate about its positive effects, to the point that even Portlandia did a sketch mocking them:

But as it turns out, plastic bag bans are a lot more symbolism than substance, and a recent study show us the reasons why: